Development of Computers

Development of Computers The earliest known device to record computations was the abacus. It dates back to ancient times and was invented by the Chinese. Ten beads were strung onto wires attached to a frame. Addition and subtraction were read from the final positions of the beads. It was considered the first manual tool used in calculating answers to problems that provided information and in a primitive way storing the results. Abacus Mechanical Clock During the Middle Ages the first closed system in terms of calculating information was invented by use of a mechanical clock. The parts of the clock calculated the time of day. The time was displayed through the position of two hands on its face. The inventor pre-programmed the clock instructions through the manner in which the pull of the weights and the swing of the pendulum with the movement of the gears established the position of the hands on the clock face. Mathematics John Napier (Scotsman mid 1600s) discovered logarith

The computer Lab and the Keyboard-Review questions

Download free latest unlimited KCSE revision papers @ - Author: Atika M. Nyamoti

 The computer Lab and the Keyboard

 Review questions

  1. How does a computer differ from a calculator?
  2. List any three safety precautions one should observe when entering a computer lab
  3. Describe any two practices that can cause fire in the computer laboratory.
  4. The keyboard has …….. groups of keys. Describe?
  5. Which key will press to:
    • Erase a letter just typed
    • Change case
    • Use numeric keypad keys
    • Indent
    • Single spacing
    • Close a pop up window
    • Activate start menu
    • Display a drop down list
    • Seek Help
    • Move the cursor upwards on a text editor
    •  Refresh current page especially web browser
  6. What is the difference between UPS and AVS?
  7. Explain the functions of the following keys on the keyboard?

  • F1
  • Shift key
  • Control key
  • Alternate key
  • Return key
  • Home key

  1. Which key will you use to overwrite the text in a sentence?
  2. Define the following words

  • clicking
  • double clicking
  • drag and drop
  • cursor
  • pointer
  • scrolling wheel

  1. Which of these devices are input devices: Mouse, keyboard, screen, CPU, Modem, Scanner, Trackball, Joy stock, IWB, Digitizer, Camera and light pen
  2. What is the use of a dehumidifier?
  3. Why should computer lab seats designed with a straight backrest?
  4. Name two preventive measures you can take to avoid loss of data.

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